A motor used for a drive source of a power window device or the like includes a motor unit, which generates rotational drive force that rotates a rotation shaft (drive shaft), and a deceleration unit, which decelerates the rotation speed of the rotation shaft and outputs the rotational drive force from an output shaft coupled to a load. The rotation shaft arranged in the motor unit and a worm shaft (output shaft) of the deceleration mechanism arranged in the deceleration unit are coupled by a clutch, which functions to transmit the rotational drive force from the rotation shaft to the worm shaft without transmitting rotational force from the worm shaft to the rotation shaft.
For instance, in a motor described in patent document 1, a mechanical clutch couples the rotation shaft and the worm shaft. The clutch includes a drive side rotation body, which is rotated integrally with the rotation shaft, a driven side rotation body, which is rotated integrally with the worm shaft, and a plurality of components coupling the drive side rotation body and the driven side rotation body.
The drive side rotation body and the driven side rotation body are arranged to axially face each other inside a cylindrical collar. A ball, which receives a thrust load, is arranged between the rotation shaft and the driven side rotation body. Three cylindrical rolling elements extending in the axial direction are arranged at equal angular intervals in the circumferential direction between an inner circumferential wall of the collar and an outer circumferential wall of the driven side rotation body. The rolling elements are supported by a support member. The support member supports the rolling elements so as to face the drive side rotation body in the circumferential direction inside the collar. Further, the collar and the support member are fixed to a gear housing that accommodates the deceleration mechanism with a stopper formed by a metal plate.
When the motor unit is driven and the rotation shaft is rotated, the drive side rotation body and the driven side rotation body are engaged in the rotation direction and rotate integrally. Thus, the rotational drive force of the rotation shaft is transmitted to the worm shaft by the drive side rotation body and the driven side rotation body, decelerated by the deceleration mechanism, and then output. In this case, the support member also engages the drive side rotation body in the rotation direction. Thus, the support member rotates integrally with the drive side rotation body along with the three rolling elements. If the rotational force is applied to the worm shaft when the motor unit is stopped, the rolling elements are sandwiched between the driven side rotation body and the collar thus inhibiting the rotation of the driven side rotation body. This inhibits transmission of the rotational force of the worm shaft to the rotation shaft.